Probiotic bifidobacterium strain

ABSTRACT

Disclosed herein is a Bifidobacterium strain isolate. It can be used as an additive to infant food and beverage products, as well as to provide a healthful bacteria to human adults and non-human mammals. The bacterium acts as a probiotic. For example, the bacterium assists newborns in producing protective acetic acid and lactic acid, as well as antimicrobials and vitamins. The bacterium can also be used to reseed bacteria levels caused by diarrhea, chemotherapy, advancing age, antibiotics, or other causes.

This invention was made with United States government support awarded bythe following agencies: NSF Grant No: INT-9020678; USDA Grant No:92-38500-7110; and USDA AGRICCREE Grant No: 91-37201-6762; HATCH #3360.The United States has certain rights in this invention.

BACKGROUND OF THE INVENTION

The present invention relates to use of a bacterial isolate as aprobiotic.

There is a desire to provide women with the option to replace humanbreast milk with manufactured formula/foods. Research indicates thatexisting infant formula/foods do not provide certain of the protectivebenefits of human breast milk. For example, bifidobacteria species areconstituents of the intestinal flora of infants. See generally R. Kok etal., 62 App. Env. Microb. 3668-3672 (1996); J.P. Langhendries et al., 21J. Ped. Gastro. Nutr. 177-181 (1995). The disclosure of thesepublications and of all other publications referred to herein areincorporated by reference as if fully set forth herein.

Acetic acid and lactic acid production, as well as production ofbacteriocins, other antimicrobials, and bioactive compounds, resultsfrom growth of Bifidobacterium and provides protective health benefits.Breast feeding appears to cause such bacteria to proliferate in humaninfants, albeit to date the mechanism by which this occurs has not beenfully elucidated.

There have been proposals to add certain strains of bifidobacteria toanimal feeds, and certain foods and beverages intended for humans. SeeJ. Luchansky, 67 Ped. Basics 2-7 (1994); J. Reiter, Dairy Foods, p. 26(March 1994); D. Hughes et al., 45 Food Tech. 74-83 (1991); U. Dubey etal., 79 J. Dairy Sci. 1146-1163 (1996).

With respect to human infants it has not previously been known where andhow newborn infants acquire the bifidobacteria which are the mostdesirable for them, which particular strain(s) of Bifidobacterium arethemost beneficial when the infant is the most vulnerable, and whetherkey strain(s) have yet to be isolated. Thus, to date infantformulas/baby foods have not proved to be sufficiently good substitutesfor human breast milk with respect to Bifidobacterium.

Also of concern is the need to provide protective affects for non-humananimals, such as by pretreating feeds with desirable bacteria, includingbifidobacteria.

Another area of concern relates to humans who have diminished levels ofdesirable bacteria in their gut for reasons other than being newborns(e.g. due to diarrhea, chemotherapy, antibiotic treatment, or advancedage). Foods, beverages, oral treatments or other probiotic techniquesfor providing desirable bacteria to humans are therefore of interest.

BRIEF SUMMARY OF THE INVENTION

The invention provides a Bifidobacterium strain designated as AmericanType Culture Collection (ATCC) #202078, in a form separate from a livehuman (e.g. an isolate). A sample has been deposited with the AmericanType Culture Collection, 10801 University Boulevard, Manassas, Va.20110-2209 on Jan. 9, 1998 with that Accession Number, under theconditions of the Budapest Treaty. This deposit does not imply or granta license to use the bacterium. A taxonomic description of the bacteriumis Bifidobacterium longum JBL 28-1/3300.

The invention also provides a food, beverage, dietary supplement, oranimal feed containing this Bifidobacterium strain. Such foods,beverages, supplements, and feeds are designed to act as probiotics whenfed orally or otherwise to humans (e.g. infants) by "seeding" the gutwith the bacterial strain.

In its simplest form, the strain can be orally fed to a human(preferably an infant) in liquid form. It can be separately swallowed,or included in newborn vitamin preparations or the like. It can also beprovided in tablets or capsules for ingestion as a dietary aid orsupplement.

Alternatively, the bacterium can be included in a beverage suitable forhumans (especially newborns), such as infant formula, fermented milk andfruit juice.

Preferred food items that can be inoculated with the bacterium are dairyproducts (such as cheese, yogurt, and ice cream). Other inoculated foodssuch as cereals, fruits and/or vegetables (such as strained apple sauceand carrots and peas) are also suitable for this invention.

In an alternative form, animal grains such as corn and soy can beinoculated with the bacterium and then fed to swine, poultry, or othernon-human mammals.

The objects of the present invention therefore include providing:

(a) a bacterial strain type that produces acetic acid, lactic acid,bacteriocins, and/or antimicrobials in a mammalian (preferably humaninfant) gut;

(b) a beverage/food/feed which can simulate certain important protectiveeffects of breast milk; and

(c) an isolated form of a bacteria which is protective for newbornhumans and both normal and health-compromised adults.

These and still other objects and advantages of the present inventionwill be apparent from the description which follows. The followingdescription is merely of the preferred embodiments. Thus, the claimsshould be looked to in order to understand the full scope of theinvention.

DETAILED DESCRIPTION General Overview

We took 196 human samples from a family (mother, infant, father,sibling). Fecal samples (especially from the newborn infant and hersibling) were found to be the major source of bifidobacteria.Importantly, no bifidobacteria were found in 6 breast milk samplestested from the mother.

A Bifidobacterium strain was found in oral and nasal samples taken fromthe infant immediately after birth, but not from these same sources whensampled later on the same day. In contrast, no Bifidobacterium strainwas recovered from 11 fecal and 6 vaginal samples within the first 37hours, but a specific Bifidobacterium strain was recovered from infantfecal samples obtained from ≧38 hours to 1 year after birth.Bifidobacteria were detected in all 11 infant samples obtained at 6months, but only in 4 out of the 13 samples obtained at 12 months.

Genomic fingerprinting via pulsed field gel electrophoresis (PFGE) wasconducted on intact genomic DNA from 16 Bifidobacterium strains from thenewborn female obtained from 6 positive samples (2 each from mouth,nose, and anus) taken immediately after birth and 1 fecal isolate fromthe second day (38 h). All 17 isolates recovered from the 7 positivesamples displayed essentially the same restriction fragment genomicfingerprints. Essentially the same fingerprint elements were alsoobserved in all 6 Bifidobacterium strains recovered from 2 fecal samplesobtained from the mother at the time of birth. Maternal feces (notbreast milk) was therefore the source of the Bifidobacterium found inthe neonate. Since the breast milk itself did not have the bacteria,breast milk appears to be a prebiotic, not a probiotic.

Bifidobacterium strains otherwise obtained from the infant within 1month, at 6 months and up to 3 years after delivery were also analyzed.Isolates recovered from the infant samples taken from delivery to 1month belonged to a single clonal type. However, isolates recovered fromsamples obtained at 6 months after birth contained three clonal types.Clonal type A was the predominant group observed in isolates frompositive samples from delivery to 1 month. It was also present inbifidobacteria at six months, but was not the predominant group at 6months.

Between 1 month and 6 months the infant was fed solid foods and receivedsome antibiotics. Thus, the different diet and/or medicine is suspectedto have caused subtle changes in the flora that were only discoverablevia the conduct of PFGE.

In addition to 6 isolates recovered from 2 fecal samples taken from themother at the time of birth, isolates from 3 fecal samples obtainedwithin 1 month after delivery also displayed the same or closely relatedgenomic fingerprints to that which predominated in the breast fed child.In contrast, 5 isolates from one vaginal sample and another 2 fecalsamples taken from the mother at the same period showed distinct genomicfingerprints. Also, isolates from the mother's fecal is samples taken at6 and 12 months displayed significantly different fingerprints.

These data indicated that a particular clone of bifidobacteriumpredominated in this mother at parturition, and, thereafter, became muchless prevalent. Isolation of this Bifidobacterium clone from a healthyinfant throughout the first 12 months is indicative of the safe natureof this bacterium in vivo. Its predominance when the infant is youngest(and thus most vulnerable) suggests its importance.

We therefore chose this strain for the ATCC deposit referred to above,and for use as a probiotic. The genomic fingerprint of this strain didnot match the genomic fingerprint of any of the known Bifidobacteriumstrains that we tested.

Isolation

As noted above, we obtained samples from a newborn infant (e.g. feces).We cultured the sample overnight at 37° C. in Reinforced Clostridalmedium, plus 0.5% propionic acid and 0.05% cysteine-HCl (pH 5.0)(RC5medium) under anaerobic conditions. We then streaked portions therefromonto RC5 agar plates, and then incubated the plates 2-3 days at 37° C.under anaerobic conditions.

We then selected milky white, large colonies for furthercharacterization and placed them in Brain Heart Infusion (BHI) brothsupplemented with 0.5% yeast extract, 0.5% dextrose and 0.05%cysteine-HCl. A representative colony was selected and submitted for thepreviously mentioned ATCC deposit.

EXAMPLES

A preferred beverage of the present invention is infant formula such asCarnation Good Start (Nestle Nutrition Division; Glendale, Calif.) thathas been inoculated with the bacterium. The bacterium can also beintroduced into various other beverages suitable for humans, especiallyinfants and toddlers. Examples could include, but not be limited to,fluid milks such as Nutrish A/B produced by Mayfield Dairy Farms(Athens, Tenn.), fermented milks such as kefir produced by Lifeway Foods(Skokie, Ill.), and/or yogurts such as Mil--Mil produced by Yakult(Japan). Other bifid-amended beverages could include fruit juices and/orsports drinks.

Preferred food items that can be inoculated with the bacterium includedairy-based products such as natural cheese, cottage cheese, and icecream. Fruits and vegetables targeted for infants/toddlers, such asapple sauce or strained peas and carrots (Gerber Products Company;Fremont, Mich.) are also suitable for inoculation. Both infant cerealssuch as rice-or oat-based cereals (Gerber) and adult cereals such asMusilix may also be suitable for this invention. In addition to foodstargeted for human consumption, animal feeds may also be suitable forinoculation. It may also be of benefit to directly inoculate newbornhumans or animals with a solution containing the preferred strain and tocontinue to dose such individuals with this strain at regular intervalsthroughout weaning and during periods of stress, diarrhea, and transit.

For some applications, it may be advantageous to also encapsulate thebacterium to better deliver, distribute, and/or protect it infoods/beverages. Likewise, it may be advantageous to include bifidogenicfactors (i.e., pre-biotics) along with the bifidobacteria (i.e.,pro-biotics) in the above mentioned foods, feeds, and supplements. Whenused together in a food, feed, or supplement, the combination of apro-biotic and a pre-biotic is referred to as a synbiotic. Bifidogenicfactors would include, but not be limited to, fructoligosaccharides suchas Raftilose (Rhone-Poulenc, Cranbury, N.J.), inulin (Imperial HollyCorp., Sugar Land, Tex.), and Nutraflora (Golden Technologies,Westminister, Colo.), as well as xylooligosaccharides,galactooligosaccharides, soyoligosaccharides, lactulose/lactitol, etc.

A particularly suitable baby formula/food can be prepared bysupplementing a powdered formula such as Carnation Good Start with about10⁶ colony forming units (CFU) of Bifodobacterium ATCC 202078 per gramof powder. Alternatively, the bifidobacteria may be encapsulated priorto the addition to the formula and/or the formula could also containbifidogenic factors at levels adequate to deliver 10 to 15 grams ofpre-biotic per day. The amended formula can then be rehydrated withwater as per the manufacturers instructions (for formula absent thebacteria), and refrigerated for at least 24 hours.

Likewise, strain ATCC 202078 could be added to cheese milk at levels of10⁶ cfu per milliliter as a starter adjunct in the manufacture ofCheddar cheese. It is also envisioned that the bifidobacteria could beblended into yogurt (e.g. frozen yogurt) or kefir to achieve levels ofat least 10⁶ cfu per gram. It may also be incorporated into tablets orcapsules for sale as a digestion aid or dietary supplement.

One could also inoculate standard animal feed (e.g. pig feed) with thisbacteria, with or without a pre-biotic. We did this with pig feed (alongwith three other strains of bacteria). The treated feed was fed tonewborn piglets and the progress of the piglets were monitored. Thepiglets showed appropriate weight gain and other characteristics,notwithstanding being subjected to the bacteria.

Industrial Application

The invention provides improved beverages, foods, and feeds, and otherproducts for increasing levels of healthful bacteria in mammalian guts.

We claim:
 1. An isolated Bifidobacterium, wherein said Bifidobacteriumis a Bifidobacterium having American Type Culture Collection designationATCC#202078.